A GNC store is seen in Westminster, Colorado October 22, 2015. REUTERS/Rick Wilking

HONG KONG/SHANGHAI (Reuters) - U.S. nutritional supplements retailer GNC Holdings is seeking a partner to boost sales in China as it battles weak revenues and a sliding share price, people with knowledge of the matter said.

Loss-making GNC (GNC.N) hopes a Chinese partner with distribution channels will lift its fortunes in the country, and has asked several companies to submit proposals this week, the sources told Reuters.

GNC, which hired Goldman Sachs (GS.N) last year to carry out a strategic review of its business which could result in a sale of the company, declined to comment on Thursday.

Chinese companies and private equity firms have expressed interest in a potential deal but several, including conglomerate Fosun International (0656.HK) and Jack Ma-backed Yunfeng Capital, pulled back as GNC’s share price continued to drop, according to people familiar with the matter.

GNC’s market value has shrunk by more than 70 percent to around $560 million since it announced the strategic review.

However, Harbin Gloria Pharmaceuticals (002437.SZ), is expected to submit a proposal this week, people familiar with the company said.

The drugmaker, based in Northeastern China’s Heilongjiang Province, had contacted lenders and private equity firms to form a consortium to acquire GNC for about $1.1 billion excluding debt, but the plan was shelved when GNC shares started to pick up in June, according to two people with knowledge of the plan.

At the time, Gloria Pharma approached China Merchants Bank (600036.SS) to finance the deal, according to the two sources.

China Merchants Bank, Gloria Pharma and Yunfeng Capital did not respond to requests for comment.

Deutsche Bank, which is advising Gloria Pharma, and Fosun International both declined to comment.

Two other sources said GNC, which named Ken Martindale, a former Rite Aid Corp executive, as chief executive on Wednesday, would be open to ideas such as an investment in its China business, but it is not considering a sale of the whole company.

GNC has been struggling with competition from online rivals and a wider move toward organic foods rather than supplements.

China, however, has been a bright spot for GNC, which sells vitamins and herbal supplements and has become one of the top sellers on China’s online shopping platforms.

China’s health supplements and vitamins market is set to grow to 168 billion yuan ($24.5 billion) by 2021 from around $18 billion last year, according to Euromonitor International, driven by increasingly health-conscious younger consumers and spurring investment by Chinese firms.